中国铬铁矿的铂族元素分布特征

DISTRIBUTION CHARACTERISTICS OF PGE IN CHROMITITES FROM CHINA

用NiS溶解和Te沉淀方法富集铂族元素（PGE），制成镍扣，再溶解于浓HCl中，使PGE和Te一起沉淀。制备的样品溶液在ELAN－5000型电感耦合等离子质谱仪（ICP－MS）上分析PGE。中国铬铁矿矿石，包括蛇绿岩套中的豆荚状铬铁矿床、非层状侵入体铬铁矿，计13个矿床（化）样品，其PGE模式表明，主要呈RU正异常模式，个别不同模式是由母岩不同以及铂族元素矿化叠加引起的。铬铁矿的PGE模式不取决于铬铁矿的化学成分，而取决于其母岩性质以及形成温度和铂族元素的熔点。

Described in this paper are the distribution characteristics of PGE in chromitites from different types of chromite deposits in China.Chromite deposits in China are divided into two types according to their geology and host rocks: ophiolite (podiform) and intrusion (non-bedded structure), and can be chemically distin guished as the high-Cr, high-Al and high-Fe types.PGE data for the chromites from 13 chromite deposits in China are reported. All the samples show depletion in PGEs with respect to chondrite-normalized diagrams. Most of the PGE patterns for the two types of chromitites are essentially the same with negative Ru anomalies.Other patterns have been identified: smooth negatively inclined patterns, generally flat patterns, patterns with lower Os and Ir contents than other PGEs and high (Pt+Pd) / (Ru +Rh+Os+Ir) ratio and patterns having the same contents of Ru, Rh, Pt and Pd. These patterns in the chromitites are related to mineralization of PGEs or host-rock type.